Individuals who are more socially conservative or religious tend to have lower sexual disgust thresholds; this relationship is hypothesized to be motivated to avoid contact with pathogens

Six dimensions of sexual disgust. Courtney L.Crosby et al. Personality and Individual Differences, Volume 156, April 1 2020, 109714. https://doi.org/10.1016/j.paid.2019.109714

Abstract: Sexual disgust is an emotion hypothesized to deter individuals from engaging in sexual activities that are probabilistically detrimental to fitness. Existing measures of sexual disgust are limited in treating sexual disgust as a unitary construct, potentially missing its multidimensional nature, and inadvertently ignoring important adaptive problems that this emotion evolved to solve. We conducted three studies to address these limitations. In Study 1, women and men (N = 225) nominated over 2,300 unique items that they considered sexually disgusting across a variety of different contexts. Study 2 (N = 331) identified a six-factor structure of the 50 most frequently nominated items: Taboo, Oral sex, Promiscuity, Hygiene, BDSM, and Same-sex attraction. Moreover, this study established construct validity with significant associations between sexual disgust and major dimensions of personality. Correlations between the Three Domains of Disgust Scale and our six-factor measure of sexual disgust established convergent validity. Study 3 (N = 318) confirmed the factor structure found in Study 2, established further convergent validity and examined sex differences and other individual differences in sexual disgust. Discussion focuses on the theoretical importance and psychometric validity of the Sexual Disgust Inventory–a new six-factor measure of sexual disgust.



3.1.3. Sexual disgust, religiosity, and political ideology
Individuals who are more socially conservative or religious tend to have lower disgust thresholds (Inbar, Pizarro, Iyer & Haidt, 2012; Olatunji, 2008). This relationship is hypothesized to exist as a function of the behavioral immune system, which motivates individuals to avoid contact with pathogens (Schaller & Duncan, 2016). This is a robust association; however, previous research has focused mostly on pathogen disgust. By measuring the associations between these variables with our measure of sexual disgust, we hope to clarify how conservatism or religious affiliation influences disgust experienced towards specific sexual acts.


5. General discussion
Sexual disgust is an understudied emotion of great importance from
an evolutionary perspective. Previous research suggests there is interesting
individual variation in the activation of this emotion. To
understand how individual variation in sexual disgust sensitivity can
persist under the winnowing forces of sexual selection, we must consider
the role of context and personality dimensions in the conceptualization
of sexual disgust. The primary focus of the studies presented
in this paper was to address the limitations of current measures
of sexual disgust, while systematically creating and testing a novel instrument
for use in future studies.

5.1. Limitations and future directions
The studies presented in this paper have several limitations that
should be considered. First, although our studies attempted to broaden
the age range and demographic distribution of the participants, selection
issues common in psychological research might still be at play.
Recruiting individuals from the university's subject pool is a common,
inexpensive way to increase sample size; however, this often results in a
young, liberal sample. The use of Amazon's Mechanical Turk helps
mitigate this issue, but only participants living in the US with internet
access could participate. Participants were demographically similar
across the three studies in terms of ethnicity, age, and sexual orientation.
However, there was variation between each study, which may
account for differences in results between Studies 2 and 3. We did not
collect data on the political orientation of individuals in Study 1. It is
possible that the individuals who participated in this nomination procedure
are not representative of politically diverse populations that
exist outside of western, economic, industrialized, rich, and democratic
samples (WEIRD; Henrich, Heine & Norenzayan, 2010). Cross-cultural
research is needed to address these issues.
It is also possible that the items generated in Study 1 do not map
exactly onto a functional analysis of sexual disgust during human
evolutionary history, but rather are a better representation of items that
individuals find disgusting within the modern environment. For example,
our measure does not include items about mating with an unattractive
person or someone with cues indicative of disease such as
open lesions, sores, or STIs. These problems, among others not included
on our measure, were presumably important deterrents during the EEA.
Future research could examine if inclusion of such items alters the latent
structure of sexual disgust.
We find it surprising that most of the sex differences that were found
in Study 2 did not replicate in Study 3, except for a significant sex
difference on the “Promiscuity” factor. The other factors of the SDI
should also be relevant for women and men's mating strategies and
should be differentially activated according to the adaptive problem
being represented. This should be especially true for items regarding
incest and rape. We believe this might be because of our sample (majority
of which was obtained through Amazon's Mechanical Turk) and
may not represent the true nature of sex differences in this emotion or
on this measure. Additional research is needed to test the robustness of
sex differences in sexual disgust across factors.
Although the studies presented in this paper provide evidence in
support of previous research relating sexual disgust to various personality
dimensions, we cannot reasonably establish the direction of
causality between these variables. It is not clear, for example, whether
conservative worldviews cause higher levels of sexual disgust or, alternatively,
whether higher levels of sexual disgust lead people to
support conservative worldviews that stigmatize sexual acts. Some links
between sexual disgust and other individual difference variables may
be the result of sexual disgust thresholds creating patterns of thoughts,
feelings, and behavior. Other links may result from pre-existing
personal characteristics—such as immune functioning, relationship
status, or formidability—involved in the calibration of sexual disgust
across development. Future research should work to disentangle the
causality of these relationships.

5.2. Hypothesized functions of the six factors of sexual disgust

Studies 2 and 3 determined a six-factor organization of sexual disgust.
These six dimensions of sexual disgust may map on to solutions to
six partially distinct adaptive problems. Understanding the proper domain
of each facet is of critical importance in predicting and interpreting
individual differences. We have hypothesized the adaptive
function of each factor below. Future research will need to examine
whether the six dimensions of sexual disgust reflect unique adaptations
that evolved in response to different adaptive problems.

5.2.1. Taboo
Engaging in the activities under the “Taboo” factor pose various
social and biological costs. Several of the items within the “Taboo”
factor are considered illegal or unusual across cultures (e.g., rape, sex
with children, sex with animals, sex with the use of human feces) while
others refer to sex with close genetic relatives. Both categories of behaviors
are often moralized and deemed unacceptable by the majority
of people. Engaging in sexual acts deemed unacceptable by one's social
group poses a serious adaptive problem: being socially ostracized.
Experiencing sexual disgust towards these activities might aid in
avoiding behaviors that can lead to social devaluation, alongside prospective
shame (Sznycer et al., 2016). Further, engaging in sex with
genetic relatives can lead to deleterious phenotypic effects in offspring.
Sexual disgust should prevent participation in these acts and promote
negative moralization of individuals who engage in these acts.

5.2.2. BDSM
Items that constitute the “BDSM” factor involve activities that are
potentially violent or dangerous. Although these items have become
less stigmatized over time (Weiss, 2006) they are still considered less
typical sexual activities. It is possible that these items are sexually
disgusting because these activities are triggering our evolved psychology
of punishment or harm avoidance, or because several of the
items represent behaviors commonly used in sexual coercion. Even
though these activities can be completely safe, sexual disgust may
function to reduce participation, thereby decreasing the potential risks
associated with harm.

5.2.3. Same-sex attraction
The “Same-sex attraction” factor may have arisen due to the way
that “disgust interacts with the ‘moral’ system” (Lieberman &
Patrick, 2018, pg. 134). Individuals engaging in sexual activities with
the same-sex have a low expected sexual value for heterosexual individuals,
and are considered a “minority group”. In our ancestral environment,
sexual disgust might have functioned to cognitively label
these individuals to eliminate the costs associated with channeling resources
or time into attempting to mate with such individuals.
Another reason this factor may have emerged centers around the
mental association between short-term mating orientation, promiscuity,
and homosexuality (Pinsof and Haselton, 2017, Pinsof &
Haselton, 2016). We found no evidence to support the idea that shortterm
mating orientation is associated with levels of disgust on the
“Same-sex attraction” factor in these studies. However, we did find that
disgust towards the “Promiscuity” factor was positively, highly correlated
with disgust towards “Same-sex attraction” in Studies 2 and 3.
Future research should work to disentangle potential reasons that this
factor emerged.

5.2.4. Promiscuity
The items that constitute the “Promiscuity” factor represent interest
in sexual variety. By engaging in acts of uncommitted, promiscuous
mating, individuals are at risk of having sex with someone whom will
not continue to be a future sexual partner, signaling themselves as an
unreliable, uncommitted mate to those in the surrounding environment,
or contracting sexually transmitted infections with increased exposure
to sexual partners and activities.
While individuals interested in sexual variety might not consider the
items on this factor overtly sexually disgusting, a potential mate who
engages in these behaviors could be costly as a long-term mate. The
replicable sex difference in levels of disgust experienced by men and
women on this factor may reflect women's desire for committed, longterm
mating as well as the costs women historically incurred from
short-term mating (Buss, 2016; Symons, 1979). Sexual disgust on this
factor should therefore function to deter individuals from facing the
potential social and health risks that are faced when one engages in
promiscuous sex (e.g., reputational damage; contracting a sexually
transmitted disease) and aid in mate selection. Future research should
examine the extent to which disgust towards “Promiscuity” is associated
with sexual regret.

5.2.5. Oral sex
The function of the “Oral sex” factor of the SDI is hypothesized to
deter participation in sexual activities that could lead to increased rates
of transmission of harmful pathogens or diseases, tapping into our
evolved psychology of disease avoidance. Genitals harbor bacteria that
can be dangerous when transmitted to other areas, either orally or
through penile-vaginal penetration (American Sexual Health
Association, 2016; Schneede, Tenke & Hofstetter, 2003). Being disgusted
by cues to increased risk of disease or pathogen transmission by
genital to mouth contact might function to protect individuals from
contracting these diseases.
Disgust towards “Oral sex” is different from disgust towards the
“Promiscuity” factor in several important ways. While it is certainly
true that engaging in promiscuous sex promotes higher disease risk,
there are a variety of other adaptive challenges that are also closely
associated with promiscuity, such as reputational damage and ensuring
investment. This is less true for “Oral sex,” because oral sex consists of
this unique, adaptive problem involving potential disease transmission
from intimate genital to mouth contact. Interestingly, the items that
constitute this factor involve acts of performing oral sex, not receiving.
It remains unclear why this asymmetry exists. Future research should
examine predictors of variation in this facet of sexual disgust.

5.2.6. Hygiene
The extraction of a factor about “Hygiene” is not surprising from an
evolutionary perspective,; but it is particularly interesting because it
provides evidence that within sexual disgust, elements of pathogen
avoidance are critical. Similar to the “Oral sex” factor, disgust towards
these items likely taps into our evolved psychology of disease avoidance.
Avoiding contact with contaminated vectors is of utmost importance
within sexual contexts. Any attempt to decrease exposure to
the pathogens involved in sexual activities would have been advantageous.
Further, bad hygiene might have been a reliable cue to increased
levels of pathogen load during our evolutionary history. Our psychology
should function to deter engaging in sexual activities that
would expose us to harmful diseases or vectors. Sex is already a risky
activity to engage in. If one is disgusted by cues to pathogens, then the
presence of bad breath or bad hygiene should further increase disgust,
inhibiting participation in sexual activities.


Future research should disentangle the adaptive function of each
factor of the SDI. If our speculations are correct, then these factors
could be linked to variation in legal rules or systems, parasite prevalence,
sexual strategies, sexual dysfunction, sexual coercion, or
childhood co-residence.. While the problems associated with the factors
of the SDI should be consistent cross-culturally, varying levels of context-
specific input might result in cross-cultural differences in sexual
disgust activation. Ecologies vary in parasite prevalence, for example,
which may evoke cultural differences in sexual disgust thresholds.
Mating pools vary in operational sex ratio, which may downregulate
“Promiscuity” disgust when there is a surplus of women, which activates
more frequent short-term mating. Cross-cultural research can test
these hypotheses, as well as examine the universality and cultural
specificity of the six factors of sexual disgust discovered in the current
studies.

Some macaques and capuchins are able to discriminate appearance from reality; seems that the evolutionary apparition of this cognitive ability was sooner than commonly believed

Are monkeys able to discriminate appearance from reality? Marie Hirel et al. Cognition, Volume 196, March 2020, 104123. https://doi.org/10.1016/j.cognition.2019.104123

Abstract: The understanding that the perceptual appearance of the environment can differ in several ways from the reality underlies the ability to discriminate appearance from reality. Being able to realize when a misperception can lead us to behave in inappropriate ways confers an evolutionary advantage and may be a prerequisite to develop a Theory of Mind. Understanding that our own perception can differ from reality seems indeed necessary to attribute to others perceptions or beliefs different than ours. This appearance-reality discrimination ability has recently been demonstrated in great apes but no information is currently available regarding this ability in other nonhuman species. In a comparative study, we tested Tonkean macaques (Macaca tonkeana), an Old World primate species, and brown capuchins (Sapajus apella), a New World primate species. We provided monkeys with two experiments using visual illusions of size and quantity to test their ability to discriminate appearance from reality, with an experimental setup similar to the one developed by Krachun et al. (2016) on chimpanzees. A large number of brown capuchins, from different ages and both sexes, as well as two Tonkean macaques succeeded in the two experiments. By ruling out all alternative explanations (i.e. visual tracking or associative learning), our study brings the first evidence that some Old World and New World monkeys are able to discriminate appearance from reality. Our results suggest moving the evolutionary apparition of this cognitive ability earlier in time. Finally, it suggests that humans could share more Theory of Mind components with more nonhuman species than we previously thought.

4. Discussion
This study brings the first evidence that monkeys are able to discriminate
appearance from reality. All our subjects passed the preference
tests of both the Lens and Mirror experiments and thus demonstrated
a strong natural preference for larger or higher number of
food items, as well as a good size and quantity discrimination ability.
Then, in the Lens experiment, all but two subjects of each species
passed successfully the basic test and the tracking control tests, demonstrating
that they were capable of ignoring the misleading appearance
of the magnified grape to choose the truly bigger one, without
being able to visual track the grapes (see Fig. 2). Afterwards, the large
number of successful brown capuchins, from different ages and both
sexes, in the last learning control brings strong evidence that they are
able to discriminate appearance from reality. In Tonkean macaques, our
results are less clear, with only one individual succeeding in the avoidlens
control (see Fig. 2). Thus, we are unable to say with confidence
whether or not this species possesses appearance-reality discrimination
ability. However, our procedure with lenses might have not allow us to
highlight AR discrimination ability in a larger scale in this species and
could provide results underestimating it (see methodological issues
discussed below). This is supported by Tonkean macaques’ good performances
in the Mirror experiment. Indeed, the two Tonkean macaques
and all but one brown capuchin that were tested in this second
experiment passed the visual tracking and the avoid-mirror tests. By
validating all controls, they demonstrated they are able to discriminate
perceived from real quantity.
We found that all except two individuals who were successful in the
Mirror experiment had also succeeded in the Lens experiment.
Successes in both of our experiments provides evidence for a general
understanding in our animals, that perceptual appearance of objects
can be different in several ways from reality. Nevertheless, we should
approach this conclusion with caution for the few individuals that
needed more than two sessions to succeed. Even by limiting the number
of sessions allowed to reach a success, our and other procedures of
progressive sessions generate an increasing probability of false positives.
To account for this multiple testing issue, one option is to look out
group performances. In this respect, brown capuchins succeeded significantly
in all tests of the Lens and Mirror experiments. For Tonkean
macaques, their succeeded significantly in all tests except for the avoidlens
tests n°1 and n°2. These results confirm our inability to conclude of
an AR discrimination ability presence for Tonkean macaques with the
Lens experiment. However, we still able to maintain confidence in our
results demonstrating AR discrimination ability in both experiments for
brown capuchins and in the Mirror experiment for Tonkean macaques.
In summary, even if more subjects of both species are necessary to make
a reliable conclusion at a species scale, results of the Mirror experiment
confirmed those of the Lens experiment and together suggest that these
monkeys could be able to discriminate appearance from reality.
The ability to discriminate appearance from reality was demonstrated
in great apes by previous studies of Karg et al. (2014) and
Krachun et al. (2009, 2016). Now, our study suggests the presence of
this ability in Tonkean macaques, an Old World monkey species, and
brings strong evidence in brown capuchins, a New World monkey
species. Therefore, the hypothesis of the emergence of AR discrimination
ability in a common ancestor dating back to at least the capuchin
monkey genus is conceivable. However, our results certainly need to be
strengthened by further research on more individuals and other species
of macaques to make a more reliable conclusion. Since only two Tonkean
macaques were compared to eight brown capuchins in both experiments,
alternative hypotheses of convergent evolution cannot be
completely ruled out. Thus, instead of looking at phylogenetic relatedness
only, our interest should go towards the socio-ecological aspects
that are characteristic of these species in order to improve our knowledge
about the development of such cognitive abilities during evolution.
Indeed, as example, many similarities were found between genus
Sapajus and Pan: long life spans, explorative and manipulative behaviours,
tool using, omnivorous diet, socially complex behaviours such
as coalitions and cooperation and so forth (Visalberghi & McGrew,
1997).
One of the major aims of this study was to compare performances of
monkey species with those of chimpanzees (Krachun et al., 2016) using
a same experimental paradigm. Like chimpanzees, brown capuchins
performed high scores in the two AR experiments and passed each test
within a small amount of sessions. Not all of them succeeded but the
proportion of successful brown capuchins is still greater than observed
in chimpanzees. Hence, the performance of brown capuchins is likely to
be comparable to those of chimpanzees in these AR discrimination
experiments. It brings more evidence that monkeys can perform like
apes in demanding cognitive tasks, for example like prerequisite ToM
tests, contrary to previous scientists’ common beliefs. These previous
studies that found differences between performances of monkeys and
apes in cognitive tasks, have normally compared apes that are highly
habituated to experiments with naive monkeys (Amici et al., 2010). In
addition to using similar standardized paradigm, our study tested
highly habituated monkeys. Thereby, a comparison between our results
and those on chimpanzees appears more reliable and appropriate.
Several recent studies on cognitive abilities comparing different
monkey and ape species found no strong evidence of a difference between
their performances (Amici et al., 2010; Meunier, 2017; Schmitt
et al., 2012; Tomasello et al., 1998). Instead, Amici et al. (2010) revealed
a link in their results between cognitive capacities and social
organisation: performances of species living in systems with fissionfusion
dynamics (e.g. chimpanzees, bonobos, orangutans, and spider
monkeys) exceeded those of species living in more stable groups (e.g.
long-tailed macaques, gorillas and capuchin monkeys). Thereby, the
type of social organisation seems to impact the physico-cognitive skills
of primates (i.e. spatial memory, quantities, causality, etc.) and may
provide better predictor of performance in some cognitive tasks than
phylogenetic relatedness (Schmitt et al., 2012). This led to the development
of the social intelligence hypothesis, which claims that primate
intelligence evolved in response to challenges of living in large and
complex groups (Byrne & Bates, 2010; MacLean et al., 2012; Schmitt
et al., 2012). However, both for Tonkean macaques and brown capuchins,
this explanation does not apply because they are not living in
fission-fusion dynamics but instead in stable female-bonded groups
with comparable social complexity, and are described as socially tolerant
(Hare et al., 2003). These other social features could then interfere
in their cognitive abilities’ development. Thus, as socio-ecological
conditions might better explain the presence of some cognitive abilities,
instead of comparing monkeys and apes, we should focus on comparison
between particular species. Studying with the same paradigm other
nonhuman primates either closely related or presenting different social
organisations (e.g. lemurs, white-faced capuchins, or long-tailed macaques)
should provide insights about the origin of this ability and
could help to clarify the social intelligence hypothesis (Byrne & Bates,
2010; Humphrey, 1976; MacLean et al., 2012; Schmitt et al., 2012).
The positive results in both experiments could be explained by
several alternative mechanisms of learning. First of all, an association
learning between large or big food item and negative outcome could be
a possibility. However, it seems to be an unlikely explanation because
our successful subjects have chosen the item that appeared larger or
bigger in the avoid tests, and they continued to choose the bigger or
larger amount of items in each warm up preference trials before each
session. Secondly, some might argue that successful individuals could
have done reverse contingency learning, i.e. choose the smaller food
item to obtain the larger one. However, this assumption is highly unlikely
for the following reasons. First, the avoid control test clearly rules
out this possibility. In fact, to validate this control, subjects needed to
choose the apparent bigger or larger food item to obtain the truly bigger
or larger one, and not the apparent smaller one as in previous tests.
Second, several studies have already demonstrated that this type of
contingency learning for both size and quantity of items is really difficult
for these species, even for great apes, and require hundreds of
trials to succeed in it (Anderson, Hattori, & Fujita, 2008; Boysen,
Berntson, & Mukobi, 2001; Krachun et al., 2009; Vlamings, Uher, &
Call, 2006).
In the Lens experiment, a few subjects did not succeed in different
tests. First, a significant left pointing bias can explain the failure of two
brown capuchins, one in the basic and the other one in the seen
tracking test. The fact that this bias was not present in the initial conditions
might indicate they do not understand the situation in the
follow-up conditions and thus could also suggest that a more ecological
procedure may have been necessary for these individuals for AR discrimination
to be revealed. Second, Tonkean macaques and brown capuchins
seem to have failed the Lens experiment in the last learning
control because they have performed learning strategies based on different
stimuli. Two Tonkean macaques and one brown capuchin obtained
really low scores, demonstrating a significant preference for the
truly smaller grape. This could be explained by a learning process to
avoid the magnifying lens or to choose the grape that appeared with the
size of the small one through the lenses. The other five unsuccessful
Tonkean macaques and one brown capuchin obtained medium scores,
which reflect a learning to choose the minimizing lens or the grape that
appeared with the size of the bigger one through the lenses. Because
neither the minimizing lens nor the grape appearing the size of the
bigger one through lenses were no more available in this control, individuals
could not anymore use these stimuli to succeed and so they
chose randomly. Moreover, these individuals who failed the test still
choose preferentially the bigger grape in warmup preference trials
before each session, suggesting their failure was not due to a change of
preference to smaller grapes.
In order to compare performances with those of chimpanzees, we
carried out a second avoid-lens test at the end of the Lens experiment
using exactly the same procedure as Krachun et al. in their study of
2016. Tonkean macaques’ results obtained in the avoid-lens test n°2 are
quite inconsistent with those of avoid-lens test n°1. In fact, one individual
succeeded in both but two individuals that failed avoid-lens
test n°1 then succeeded in the avoid-lens test n°2, within one or two
sessions only. For these two subjects, we carried out one more session
with the unseen test procedure, in order to check whether by changing
again sizes and lenses used, they will succeed (as before in the same
unseen tracking test) and thus demonstrate a truly understanding of the
illusion phenomena. However, both of them drastically failed by never
choosing the truly larger grape in this session. These results highlight a
learning strategy they must have developed during the four sessions of
the avoid-lens test n°1. Because avoid-lens test n°2 was carried out after,
individuals had the possibility to learn the new rule (larger grape
placed behind magnifying lens). In addition, the only subject that
passed the first avoid-lens control test needed four sessions to succeed
in this last control. His result should be interpreted with caution because
he could have also learned, faster than the others, i.e. within only
three sessions. Surprisingly, the other Tonkean macaques and brown
capuchins that have failed did not realise this potential quick learning:
they both failed the avoid-lens n°1 and the avoid-lens n°2. A comparison
between avoid-lens n°1 performances of Tonkean macaques and brown
capuchins with avoid-lens test performances of chimpanzees in the
study of Krachun et al. (2016) seems thus more reliable.
Instead of an absence of AR discrimination, individuals’ failure
could be interpreted by other explanations corresponding to methodological
issues like too many experimenter’s manipulations or isolation
from their social group. Our test procedure could have required too
much concentration, motivation and short-term memory for these animals,
difficulties faced by Krachun et al. (2016) in their study on
chimpanzees. Notably, poor performances of Tonkean macaques (poor
success ratio, higher means of sessions to succeed in each test) compared
to brown capuchins and chimpanzees may support this assumption:
as we carried out half-sessions for brown capuchins, they had
twice as many demo trials as Tonkean macaques and chimpanzees,
hence more opportunities to understand the effects of stimuli illusion.
Moreover, all brown capuchins came to the experimental room at least
once per day, whereas with some Tonkean macaques, several days
sometimes separated two successive sessions because they did not come
back in the experimental room regularly. Because of those delays,
Tonkean macaques might have faced memory challenges about the
impact of illusion. Our results could thus underestimate their AR discrimination
ability.
Given the pointing bias of some brown capuchins and the large
failure of Tonkean macaques in the Lens experiment, ecological relevance
of our paradigm has to be questioned. The better success ratio
in the Mirror experiment could be due to the applied illusion. The
mirror effect indeed creates a false presence of two raisins, which do not
exist in reality. Whereas lens is modifying properties of grapes that
already exist, it does not create new food items. Thereby, it is maybe
easier to understand the effect of a mirror than the subtle modification
of existent items created by lenses. One alternative paradigm to test size
illusion understanding could be the one developed by Karg et al.
(2014). In their comparative study between great apes and children on
AR discrimination, they created a size illusion using completion illusion,
i.e. part of an object is partially occluding by another, in order to
inverse size relation. As Tonkean macaques and brown capuchins are
semi-arboreal primates, they might more regularly face size illusion
challenges by completion illusion because of the dense vegetation in the
canopy rather than by distortion.
Further research using different complementary types of illusion,
e.g. colour or auditory illusions, could now bring more information
about the scope of the AR understanding of these species. Another
notable result is that several capuchins of various ages succeeded. Thus,
AR discrimination ability seems to appear early in the development of
brown capuchins. Further experiences on even younger individuals will
be helpful to determine if the development of AR discrimination occurs
around the same development stage as for human children and with the
same developmental pattern (e.g. Hansen & Markman, 2005; Karg
et al., 2014; Moll & Tomasello, 2012).
To conclude, our results support those of apes, demonstrating that
this AR discrimination ability is not unique to great apes. As we have
now demonstrated that even some monkey species seem to possess this
understanding, it seems these abilities are perhaps more evolutionary
ancestral than previously thought. More research on different monkey
species with similar standardized procedure is now more than ever
necessary to better understand evolution of our remarkable social
cognition.

The more maladaptive forms of narcissism (hypersensitivity, willfulness) declined across life & individual autonomy increased; later-born birth-cohorts were lower in hypersensitivity & higher in autonomy

Chopik, William J. 2019. “Longitudinal Changes and Historic Differences in Narcissism from Adolescence to Older Adulthood.” PsyArXiv. December 10. doi:10.31234/osf.io/bf7qv

Abstract: In the debate about whether or not narcissism has been increasing in recent history, there is a lack of basic information about how narcissism changes across the adult lifespan. Existing research relies on cross-sectional samples, purposely restricts samples to include only college students, or follows one group of individuals over a short period of time. In the current study, we addressed many of these limitations by examining how narcissism changed longitudinally in a sample of 747 participants (72.3% female) from age 13 to age 77 across six samples of participants born between 1923 and 1969. Narcissism was moderately stable across the lifespan (rs ranged from .37 to .52), to a comparable degree as other psychological characteristics. We found that more maladaptive forms of narcissism (e.g., hypersensitivity, willfulness) declined across life and individual autonomy increased across life. More later-born birth-cohorts were lower in hypersensitivity and higher in autonomy compared to earlier-born birth-cohorts; these differences were most apparent among those born after the 1930s. The results are discussed in the context of the mechanisms that drive both changes in narcissism across the lifespan and substantive differences in narcissism between historical periods.


Discussion

The current study examined changes in narcissism from age 13 to age 77 across six different studies of human development. Narcissism was moderately stable across the lifespan, to a comparable degree as other psychological characteristics (Roberts & DelVecchio, 2000). We found that more maladaptive forms of narcissism (e.g., hypersensitivity, willfulness) declined across life and autonomy increased across life. Later-born birth-cohorts were lower in hypersensitivity and higher in autonomy, which is consistent with one study on historical changes in narcissism (Wetzel et al., 2017) but also in strong contrast to studies suggesting that later-born birth-cohorts are higher in narcissism than earlier-born birth-cohorts (Twenge, 2006; Twenge et al., 2008). The current study is one of the most comprehensive examinations of narcissism changes ever conducted and included data from individuals born throughout a 46-year period (from 1923 to 1969).
The current findings are consistent with tenets of the social investment model of personality development (Roberts et al., 2005). Specifically, although narcissism may serve some protective role for well-being in emerging adulthood (Hill & Roberts, 2012), high levels of maladaptive forms of narcissism are incompatible with the age-graded social roles and expectations that individuals adopt throughout the lifespan. Psychological characteristics are thought to change in response to the complex interplay of individuals functioning within the demands and expectations of increased responsibility and maturity. As a result, maladaptive forms of narcissism that serve as a barrier to success in work, life, and love are abated throughout middle age and older adulthood. Forms of narcissism that enhance successes in these domains are likely to be cultivated. For these reasons, maladaptive forms of narcissism tend to decline across life and adaptive forms of narcissism tend to increase across life.

Birth-cohort Effects on Narcissism

That later-born birth-cohorts were lower in hypersensitivity and higher in autonomy was also perplexing as it goes against a narrative that recent birth-cohorts have experienced a monotonic rise in narcissistic traits across the past century (Twenge et al., 2012a, 2012b; Twenge et al., 2008). It is not necessarily surprising that maladaptive narcissism is declining while autonomy is increasing, as these two are inextricably linked (Deffler, Leary, & Hoyle, 2016). Although some research has found similar (decreasing) levels of maladaptive narcissism, the reasons behind such differences have not been thoroughly examined. There are many substantive and non-substantive differences between birth-cohorts and previous work has tried to identify a number of social indicators for why birth-cohorts might psychologically differ (e.g., technological changes, changes in parenting styles; Konrath et al., 2011). Exactly how these differences translate into mean differences in some forms of narcissism and not others is an exciting direction for future research. Of course, as with gender, the samples were not perfectly comparable with respect to ages distributed across the birth-cohorts. For example, some samples (e.g., the Radcliffe Sample) had only participants who were middle age and older. Other samples (the Block and Block Sample) had only participants who were young adults. Thus, sample/birth year and age are somewhat conflated in the current study. Thus, we interpret caution when drawing conclusions from the birth-cohort analyses.

Limitations and Future Directions

The current study had many strengths. We combined data from six distinct sources to model changes in narcissism over a 59-year period. Nevertheless, there are some limitations that are worth noting.
Why did people change in narcissism over time? Other than the sample imbalance with respect to age and gender (see above), we did not have a consistent set of predictors to model the mechanisms underlying lifespan changes and birth-cohort differences in narcissism over time. Like other traits that function within the social investment framework, there are likely both selection and socialization factors that drive the development of narcissism across the lifespan (Specht et al., 2014; Specht, Egloff, & Schmukle, 2011). For example, people high in autonomy might select environments that are conducive to cultivating their autonomous lifestyle (and avoid situations that dampen it). Likewise, once individuals have selected an environment, there are additional mechanisms that drive stability and change in narcissistic characteristics as these changes are socialized within individuals (Caspi & Roberts, 1999). What are the environments and life circumstances that initiate changes in narcissism? And which environments and life circumstances lead to sustainable changes in narcissism over long periods of time? Although there is a great deal of research highlighting narcissists’ resilience and resistance to critical feedback about themselves (Bushman & Baumeister, 1998), some studies show some promising signs that narcissists can change in response to life events (Grosz et al., 2017). Nevertheless, the mechanisms through which narcissists are able to reflect on their lives in an impartial way and consciously change their thoughts and actions are currently unknown, even though it appears that narcissists do have some accurate self-insight into their personalities (E. N. Carlson, 2013; E. N. Carlson, Vazire, & Oltmanns, 2011). Future research can more formally model individual differences in changes in narcissism and the conditions under which lifespan changes are largest.

* Why do birth-cohorts differ in narcissism over time? Likewise, it is worth noting that our study did find reliable differences in narcissism between birth-cohorts, but in the reverse direction than is typical seen (Wetzel et al., 2017). Just as it is important to examine predictors of lifespan changes in narcissism, it is also important to examine whether changes in narcissism can be attributable to changes in parenting behaviors, shifting demographics and the relative risk of exposure to life events, some broader cultural changes, or another explanation entirely (Konrath et al., 2011; Twenge et al., 2008). Because the studies did not have consistent or, in some cases, any variables to operationalize changes in these variables, we are left with merely descriptive data on how narcissism might change over historical time. We view this as a major limitation to the current report and hope that future researchers can more seriously conceptualize and test why birth-cohorts might be changing in narcissism. That two of the samples were comprised entirely of women is also a considerable limitation, particularly for the birth-cohort analyses. Worth noting, because of the gender differences found in narcissism facets, it is likely that the birth-cohort differences cannot be entirely attributable to the gender composition of the sample. In other words, samples comprising entirely of women were often still higher than samples containing both men and women. Of course, the differences we observed in the current study are likely the combination of substantive changes in psychological and demographic variables. Future research can have more balanced gender designs with respect to gender and other demographic characteristics.

* How do researchers measure narcissism changes in secondary data sources? In the current study, we relied on just one of many models of narcissism—Wink’s (1992a) conceptualization of hypersensitivity, willfulness, and autonomy. The operationalization and measurement history of narcissism is long and controversial, with several alternative models and measures portending to measure narcissism’s core features (Ackerman et al., 2011; Back et al., 2013; Campbell, Bonacci, Shelton, Exline, & Bushman, 2004; Glover, Miller, Lynam, Crego, & Widiger, 2012; Konrath, Meier, & Bushman, 2014; Pincus et al., 2009; Raskin & Terry, 1988; Wink, 1991). Our choice to use Wink’s conceptualization was primarily (and necessarily) driven by an effort to maximize the available data across the six studies.
However, in directly comparing the CAQ scales to more contemporary measures of narcissism (e.g., NPI, NARQ), we found that one facet in particular—autonomy—had relatively small overlap with other measures of narcissism (rs < |.28|). In previous research, the CAQ autonomy scale was often conceptualized as a form of adaptive narcissism (Cramer, 2011a; Wink, 1992a). However, in our very preliminary examinations, it appears that these items capture autonomy as a broader individual difference characteristic than a form of adaptive narcissism per se. Thus, our and others’ necessary reliance on using CAQ autonomy as a form of adaptive narcissism is likely misplaced. This limitation speaks to a larger concern for researchers who use secondary data to examine changes in characteristics that were not intended to be measured in the original data collection. Running additional studies to verify the convergent and criterion validity of researcher-generated scales in the context of secondary data analysis is not particularly expensive; the benefits of adopting such an approach are numerous though. The danger is in liberally using measures form secondary data sources without formally examining their conceptual meaning and empirical validity. Indeed, such ready adoption of measures is likely one of the contributing factors for why some concepts (e.g., adaptive narcissism) might become so broad as to assume related, but technically different concepts (e.g., autonomy)(Haslam, 2016). For hypersensitivity and willfulness, there was substantial overlap with other measures of narcissism, suggesting that these aspects of narcissism may be less problematic to continue using in future research. Nevertheless, more formal efforts to examine how the developmental trajectories of different narcissism inventories vary would be an exciting direction for future research.
Although our use of a quasi-accelerated longitudinal design had many strengths, including measuring changes in narcissism over a 64-year period and across multiple birth-cohorts, its use also presents several unique limitations. For example, no one person was followed from age 13 to age 77, severely limiting our ability to truly isolate lifespan changes in narcissism. Further, because the studies had large gaps in between assessment points, we were limited in our ability to assess more nuanced developmental changes.

European elections & support for governing parties over time: Anticipating being completely satisfied (as compared to completely dissatisfied) is associated with around a 6.5% higher probability of declaring support for such parties

Happiness and Voting: Evidence from Four Decades of Elections in Europe. George Ward. American Journal of Political Science, December 9 2019. https://doi.org/10.1111/ajps.12492

[An earlier working paper version of this article circulated under the title “Is Happiness a Predictor of Election Results?”]

Abstract: There is a growing interest among policy makers in the use of subjective well‐being (or “happiness”) data to measure societal progress, as well as to inform and evaluate public policy. Yet despite a sharp rise in the supply of well‐being‐based policy making, it remains unclear whether there is any electoral demand for it. In this article, I study a long‐run panel of general elections in Europe and find that well‐being is a strong predictor of election results. National measures of subjective well‐being are able to explain more of the variance in governing party vote share than standard macroeconomic indicators typically used in the economic voting literature. Consistent results are found at the individual level when considering subjective well‐being and voting intentions, both in cross‐sectional and panel analyses.


Discussion

Various countries around the world have recently begun to go “beyond GDP” by measuring subjective well-beingon a large scale and using the data (1) as a general measure of societal success and progress, (2) to guide and inform policy decisions, and (3) to evaluate the outcomes of government programs (Durand 2018; O’Donnell et al.2014). These practices are likely to continue to grow,in part because SWB is able to pick up the benefitsof a great deal of government activity that traditional economic outcomes may struggle to (Krueger and Stone2014).19 

Yet despite the recent sharp rise in the supply of SWB-based public policymaking, an open empiricalquestion is whether there is any electoral demand for it.The findings presented in this article suggest there maybe significant electoral incentives for politicians seeking reelection to consider SWB when deciding upon policypriorities.Global, cognitive evaluations of life are currently themost widely used measure of SWB by researchers inthe economic literature as well as by policy makers, but life satisfaction is only one component of SWB. Large-scale data on the emotional states of citizens are becoming more prevalent and are beginning to provide policymakers with a fuller picture of national SWB (Kahneman et al. 2004; Krueger and Stone 2014). Further research should investigate the extent to which measures of posi-tive and negative affect, as well as eudaemonic measures of purpose, are able to add to our understanding of vot-ing behavior.A further dimension of SWB is temporal: Although the main analysis of this article studies voters’ currentlevels of life satisfaction, it may be that future expectation sof life satisfaction are just as—or even more—important in driving vote choice. In a subset of waves of the German SOEP, respondents were asked about their anticipated life satisfaction in 5 years’ time, using the same 0–10 response scale as with current life satisfaction. In Table A1, I find that people’s future life satisfaction dominates current life satisfaction when it comes to predicting support for governing parties within people over time. Anticipating being completely satisfied (as compared to completely dissatisfied) is associated with around a 6.5% higher probability of declaring support for a governing party.20 

Open to further research is the broader questionof what array of determinants of SWB, and potentiallywhich domains of SWB, drive the link between nationalhappiness and election results—and ultimately what incumbents might do to improve their chances of reelec-tion. Although SWB has been shown to be determinedby a host of policy-relevant yet noneconomic variables,including physical and mental health, environmenta lquality, social cohesion, crime and corruption, quality of government services, and education (see, e.g., Clark et al.2018; Diener et al. 1999; Dolan, Peasgood, and White2008), the analysis of Liberini, Redoano, and Proto (2017)suggests voters may also reward/punish incumbent politicians for boosts and dips in their happiness that arecaused by factors outside of government control. Further research may continue to investigate (1) the extent to which voters are able (or willing) to filter which elementsof their well-being provide useful information about thequality and effort of incumbents, and (2) the theoretical implications of this for our understanding of democratic accountability.21 

Although SWB is a stronger predictor of incumbent vote share in general elections than economic growth, un-employment, or inflation, macroeconomic variables are nevertheless significant predictors of government elec-toral success conditional on national happiness. Equally,at the individual level, SWB and personal finances are in-dependently predictive of voting intentions. This suggests politicians face multiple incentives to improve people’s economic as well as broader non economic well-being.Future theoretical work may look to model these dynam-ics within a multitask political agency framework.22 

The data used here are observational, and it isworth reiterating that it is not possible to interpret thee mpirical associations presented in this article causally. 

Rather, the analysis is focused on determining what bestpredicts the electoral fate of governing parties. Despite this important caveat, however, a causal interpretation of the findings is suggested by Liberini, Redoano, and Proto(2017), who leverage exogenous variation in SWB to demonstrate a causal mechanism between happiness and self-reported incumbent voting intentions. The analysis presented here suggests that this effect is also evident atthe national level, across 15 countries over four decades, in real-world elections.

When male employees are assigned to male managers, they are promoted faster in the following years than they would have been if they were assigned to female managers, due to socialization between employees & managers

The Old Boys' Club: Schmoozing and the Gender GapZoë B. Cullen, Ricardo Perez-Truglia. NBER Working Paper No. 26530, December 2019https://www.nber.org/papers/w26530

Abstract: The old boys’ club refers to the alleged advantage that male employees have over their female counterparts in interacting with powerful men. For example, male employees may schmooze with their managers in ways that female employees cannot. We study this phenomenon using data from a large financial institution. We use an event study analysis of manager rotation to estimate the causal effect of managers’ gender on their employees’ career progression. We find that when male employees are assigned to male managers, they are promoted faster in the following years than they would have been if they were assigned to female managers. Female employees, on the contrary, have the same career progression regardless of the manager’s gender. These differences in career progression cannot be explained by differences in effort or output. This male-to-male advantage can explain a third of the gender gap in promotions. Moreover, we provide suggestive evidence that these manager effects are due to socialization between male employees and male managers. We show that these manager effects are present only if the employee works in close proximity to the manager. We use survey data to show that, after transitioning to a male manager, male employees spend more time with their managers. Finally, we study a shock to socialization within males, based on the anecdotal evidence that employees who smoke tend to spend more time together. We find that when male employees who smoke switch to male managers who smoke, they spend more of their breaks with their managers and are promoted faster in the following years. Moreover, the effects of these smoking manager switches are similar in timing and magnitude to the effects of the gender manager switches.

Dim Ambient Lighting Increases Game Play Duration and Total Spend

Hidden in the Dark: Dim Ambient Lighting Increases Game Play Duration and Total Spend. Jasmina Ilicic, Stacey M. Baxter. Journal of Gambling Studies, December 10 2019. https://link.springer.com/article/10.1007/s10899-019-09921-5

Abstract: It has been suggested that much like commercial environments (e.g., retailing), the situational characteristics of gambling environments form an important determinant of gambling behavior. However, no research has examined whether ambient lighting in gaming venues can have unintended consequences in terms of gambling behavior. The results of three experimental laboratory studies show that game play duration and total spend increase when ambient lighting is dim (vs. bright). Process evidence suggests that this phenomenon occurs as ambient lighting influences risk-taking, which in turn increases game play duration and total spend. Further, evidence is provided that the effect of dim (vs. bright) ambient lighting reduces risk-taking and subsequent game play duration and total spend when an individual’s self-awareness is facilitated (i.e., screening between gaming machines is removed). This research has implications in terms of public policy regarding the determination of minimum lighting levels in venues as a means to decrease gambling-related harm. Moreover, while gaming venues can use these insights and their ambient lighting switches to nudge individuals toward reducing their game play duration and total spend, gambling-afflicted consumers can opt for gambling venues with bright ambient lighting and those without screened gaming machines.

Keywords: Gambling Ambient lighting Risk-taking Self-awareness Game play duration Total spend


General Discussion

We introduced ambient lighting in gaming venues as an important sensory situational char-acteristic that can be easily adjusted to influence gambling behavior in terms of game play duration and total spend. Results of this research provide evidence that dim ambient light-ing can cause increased gambling behavior in terms of game play duration and total spend, whereas bright ambient lighting can decrease game play duration and total spend. We pro-vide evidence of the process underlying this effect, which we confirm is risk-taking. Dim ambient lighting, as opposed to bright ambient lighting, enhances risk-taking propensity, increasing subsequent game play duration and total spend. Further, we propose and dem-onstrate that the negative effect of dim ambient lighting on risk-taking and on subsequent game play duration and total spend is attenuated when self-awareness is facilitated through the absence of screening between machines. In other words, risk-taking and subsequent game play duration and total spend is decreased when individuals are made more self-aware through the absence of screening between gaming machines in dim lighting con-ditions. Our results provide insights into reducing gambling-related harm in gaming ven-ues and also provide interesting insights for public policy related to luminance levels and screening in gaming venues.In light of our findings, gaming venue operators could encourage more responsible gambling behaviors by adjusting their ambient lighting levels to reduce gambling-related harm to their customers and to decrease their risk-taking propensity. As such, we suggest the following guidelines be adopted by gaming venues to encourage responsible gambling behavior:1. Ensure that ambient lighting levels are bright.2. Use lighting adjusters to increase the lux within gaming venues or alter the bulbs used to brighter levels.3. Avoid the use of screening between gaming machines, which increases risk-taking and gambling behavior in dim ambient lighting conditions.We also suggest that our findings have important implications for public policy and regulations in the gaming industry. We suggest that public policymakers review the dim-luminance lighting level requirements for gaming venues. Brighter ambient lighting is suggested in order to reduce the harm associated with dim ambient lighting on gambling behavior. Furthermore, public policymakers should incorporate screening requirements into regulations. Specifically, we suggest the removal of screening between machines to create an open space that enhances self-awareness and reduces gambling-related harm.Research has found that lighting plays a significant role in influencing gambling behav-ior (e.g., Stark et al. 1982; Griffiths and Parke 2003; Spenwyn et al. 2010). Researchers have typically examined the effect of lighting in terms of the colors that are emitted from gaming machines themselves. For example, research suggests that individuals take greater risks and bet more frequently when gambling on machines that omit red, rather than blue, light (Stark et al. 1982). However, our research extends this body of work by providing evidence that the situational characteristics of ambient lighting within gaming venues can influence gambling behavior in terms of game play duration and total spend. This is espe-cially important for gaming venue managers in adjusting lighting levels to nudge more responsible gambling behavior.

Limitations and Directions for Future Research

This research is not without limitations. This research was conducted within an artifi-cial environment in a controlled laboratory setting. Although a controlled environment is desirable to be able to make casual inferences regarding the effects of ambient lighting on game play duration and total spend, the laboratory environment did not represent real-life gaming environments that include sounds, smells, flashing and colored lights from gam-ing machines, and a variety of gaming machine options available. We suggest that future research conduct a field study in which the ambient lighting levels are adjusted in real gam-ing venues, collecting data regarding game play duration and total spend, as well as other key gambling-related measures, such as numbers of bets and types of bets. Although it is acknowledged that field studies are difficult to implement, venue operators may be more willing to cooperate if only one smaller room were used as a test. This would minimise the impact of the study on operations.Our research is also limited as it only included a student sample and was conducted in Australia. We argue, however, that adolescents or young adults are particularly susceptible to the harm associated with situational characteristics that may encourage gaming machine use, as research shows that electronic gaming machine players are more likely to be in the 18- to 24-year-old age group (Delfabbro 2012). We also suggest that Australia is a par-ticularly vulnerable country to examine, as it holds the 2016 record in terms of losses per inhabitant; losing on average A$990 per adult resident, half of which is due to gaming machines (Pancani et al. 2019). Future research should explore the effects of ambient light-ing on gambling behavior across a wider sample of individuals, as well as across a variety of countries, to examine whether there are any age-related or cultural differences that may be observed.Furthermore, our study examined only two levels of luminance (i.e., 500 lux (bright) and 40 lux (dim)). Future research should examine varying levels of luminance to identify the point of luminance at which ambient lighting can have negative effects on gambling-related behavior. This would also have important implications regarding the specificity of luminance levels for public policy regulations.

First evidence of the acoustic correlates of cooperative behaviour: Men with lower‐pitched voices & greater pitch variations were more cooperative; however, testosterone did not influence cooperative behaviours

Does he sound cooperative? Acoustic correlates of cooperativeness. Arnaud Tognetti, Valerie Durand, Melissa Barkat‐Defradas, Astrid Hopfensitz. British Journal of Psychology, December 9 2019. https://doi.org/10.1111/bjop.12437

Abstract: The sound of the voice has several acoustic features that influence the perception of how cooperative the speaker is. It remains unknown, however, whether these acoustic features are associated with actual cooperative behaviour. This issue is crucial to disentangle whether inferences of traits from voices are based on stereotypes, or facilitate the detection of cooperative partners. The latter is likely due to the pleiotropic effect that testosterone has on both cooperative behaviours and acoustic features. In the present study, we quantified the cooperativeness of native French‐speaking men in a one‐shot public good game. We also measured mean fundamental frequency, pitch variations, roughness, and breathiness from spontaneous speech recordings of the same men and collected saliva samples to measure their testosterone levels. Our results showed that men with lower‐pitched voices and greater pitch variations were more cooperative. However, testosterone did not influence cooperative behaviours or acoustic features. Our finding provides the first evidence of the acoustic correlates of cooperative behaviour. When considered in combination with the literature on the detection of cooperativeness from faces, the results imply that assessment of cooperative behaviour would be improved by simultaneous consideration of visual and auditory cues.



Discussion

Several acoustic features influence the perception of how trustworthy and cooperative the speaker is (Belinet al., 2017; Knowles & Little, 2016; Montano et al., 2017; O’Connor& Barclay, 2017; Oleszkiewicz et al., 2017; Ponsotet al., 2018; Tigue et al., 2012; Tsantani et al., 2016). Their influence could stem from the pleiotropic effect of testosterone on both acoustic features and cooperative behaviours (O’Connor & Barclay, 2017). It is unknown, however, whether acoustic features are associated with actual cooperativebehaviour and whether testosterone mediates this association. In this study, we presentevidence that both vocal pitch and its variations are related to cooperative behaviour in anincentivized social-dilemma game: the public good game. However, no effect oftestosterone level on cooperation, or on any of the other acoustic features studied, wasfound. Overall, ourstudy providesthe first evidence of the existence of acoustic correlates of cooperativeness.

Specifically, our results indicate that men’s contributions to the public good aresignificantly and negatively associated with fundamental frequency and significantly andpositively with its variations. When we compared the acoustic traits between conditional cooperators and free-riders (the two main categories as defined in Fischbackeret al.(2001)), we found that conditional cooperators exhibit significantly higher pitch variations than free-riders. Taken together, our results suggest that highly cooperative men have deeper voices and exhibit greater variations in their intonation compared to less cooperative men.The present results are consistent with the only previous study examining jointly the influence of vocal pitchand its variations on the perception of a speaker’s cooperativeness (Knowles & Little, 2016). Indeed, Knowles and Little (2016) found that male voices wereperceived as the most likely to cooperate when they exhibited high pitch variations in combination with a low pitch (although it was found for women’s but not for men’sratings). Vocal pitch and its variation are, thus, associated in the same way with bothcooperative behaviours and perceived cooperativeness. It, therefore, indicates that inferences of cooperativeness from voices might actually facilitate the detection ofcooperative partners. This sets the ground for future research, namely whether particular ombinations of acoustic traits influence ratings of cooperativeness and to which degreethese acoustic cues of cooperativeness are reliable or could be manipulated throughconscious control of the speaker (e.g., by lowering voice pitch or by increasing speech’sintonation).Behavioural decisions in the public good games (contributions to the public good) andin the trust game (amounts sent to the other player) are highly correlated (Galizzi & Navarro-Mart ınez, 2018; Peysakhovich, Nowak, & Rand, 2014), which suggests a strongassociation between cooperativeness and trustworthiness. Hence, similarly to cooper-ativeness, vocalpitchand itsvariationsarealso likelytobe used ascues oftrustworthiness.

In fact, both acoustic features influence perception of how trustworthy a speaker is. For example, lower-pitched male voices and voices with high pitch variations are perceived asmore trustworthy in general (Belinet al., 2017; Oleszkiewicz et al., 2017; Schirmer et al.,2019; Tsantaniet al., 2016) or when trust is linked to the political context (Klofstadet al.,2015, 2012; Tigueet al., 2012). It remains unknown, however, whether these acousticfeatures correlate with actual trustworthiness, and not only with perceived trustworthiness.The existence of vocal cues of cooperativeness could stem from the pleiotropic effectof testosterone on both cooperative behaviours (Burnham, 2007; Diekhofet al., 2014; Reimers & Diekhof, 2015; Takagishiet al., 2011) and vocal pitch (Dabbs & Mallinger,1999; Evanset al., 2008; Putset al., 2012). As testosterone has immunosuppressive effects (immunocompetence handicap hypothesis: Folstad & Karter, 1992; Rantalaet al., 2012;but see: J. Nowak, Pawłowski, Borkowska, Augustyniak, & Drulis-Kawa, 2018), men with(costly) lower pitch might benefit from a higher biological quality (Arnocky, Hodges-Simeon, Ouellette, & Albert, 2018; Hodges-Simeonet al., 2015). In addition, they may also be more socially dominant (Puts et al., 2012; Puts, Gaulin, & Verdolini, 2006; Putset al.,2007). Accordingly, because of their underlying qualities, including access to resources,men with lower pitch would be more cooperative than men with higher pitch becausethey could better afford the costs associated with cooperative behaviours while receiving reputational benefits (Raihani & Smith, 2015; Sylwester & Roberts, 2010; Tognetti,Berticat, Raymond, & Faurie, 2012; Tognettiet al., 2016). This condition-dependent mechanism could ensure the reliability of the vocal cues of cooperativeness. However, in the present study testosterone levels did not seem to affect cooperation or any of theacoustic features studied. Testosterone is a multiple-effect hormone which is influencedby numerous biological and environmental factors and pathways. As such, it is generally difficult to correlate testosterone levels to other biological or behavioural traits. Inaddition, we could only collect one sample of saliva for hormonal assays, which might notaccurately reflect a participant’s basal testosterone level.

Although the present study retains many strengths, it is also subject to several limitations. In particular, it is the first to investigate the existence of acoustic correlates ofcooperativeness in speech production. However, the investigation is restricted to Frenchmen. To provide broader conclusions, it should not only be extended to women, but toother populations as well. In addition, we did not conduct a perceptual study using ourrecordings to examine whether listeners use acoustic features as a social cue in abehavioural economic task. Indeed, we recorded individuals’ free speech due to itsstronger ecological validity (Puts e tal., 2007; Suireetal., 2018), but this type ofrecordingsis not suitable for perceptual studies, as recordings roughly differ in duration and semanticcontent. Finally, we used state-of-the-art methodology in economics to quantify andcategorize individuals according to type (Fischbacheret al., 2001). However, wecompared two categories with unbalanced sample sizes (NFree-rider=11 vs.Nconditionalcooperator=44) and the sample size of the free-riders was limited (although its proportion(18%) mimics the proportion found in the general French population; Frey, 2017). Hence,we cannot exclude the possibility that the acoustic differences found between free-ridersand conditional cooperators arose from this specific and particular sample of 11 free-riders. It seems, nevertheless, unlikely as the results found using this categorization arequalitatively similar to the ones we found using a continuous measure of cooperativeness(i.e., contributions to the public good).

To conclude, the present study provides evidence that at least two acoustic features(vocal pitch and its local variations) could be used as cues of cooperativeness. Facial cuesenable individuals to discriminate between high and low cooperative individuals with anabove chance accuracy (Bonnefon et al., 2013, 2017; Fetchenhauer et al., 2010; Little et al., 2013; Oda, Naganawa, et al., 2009; Reedet al., 2012; Stirrat & Perrett, 2010, 2012;Tognettiet al., 2013) but the accuracy of face-based cooperation detection is rather low (Bonnefon et al., 2017). Hence, by highlighting the fact that cooperativeness is advertisedby several cues across multiple sensory modalities, our findings pave the way for further investigations examining whether the assessment of cooperative behaviour is improved by simultaneous consideration of both visual and auditory cues.

Economic status cues from clothes affect perceived competence from faces — The Habit Does Make The Monk in the End

Economic status cues from clothes affect perceived competence from faces. DongWon Oh, Eldar Shafir & Alexander Todorov. Nature Human Behaviour, December 9 2019. https://www.nature.com/articles/s41562-019-0782-4

Abstract: Impressions of competence from faces predict important real-world outcomes, including electoral success and chief executive officer selection. Presumed competence is associated with social status. Here we show that subtle economic status cues in clothes affect perceived competence from faces. In nine studies, people rated the competence of faces presented in frontal headshots. Faces were shown with different upper-body clothing rated by independent judges as looking ‘richer’ or ‘poorer’, although not notably perceived as such when explicitly described. The same face when seen with ‘richer’ clothes was judged significantly more competent than with ‘poorer’ clothes. The effect persisted even when perceivers were exposed to the stimuli briefly (129 ms), warned that clothing cues are non-informative and instructed to ignore the clothes (in one study, with considerable incentives). These findings demonstrate the uncontrollable effect of economic status cues on person perception. They add yet another hurdle to the challenges faced by low-status individuals.


Discussion 
Across studies, we found that economic status clothing cues influenced competence judgements of faces. The effect persisted when faces were presented very briefly (that is, 129 ms), when informa-tion was provided related to the person’s profession and income, when formal clothing was replaced by more casual clothing, when participants were advised to ignore the clothing, when they were warned that there was no relationship between clothing and com-petence before choosing rather than rating faces, and when partici-pants were offered a monetary reward for accuracy. These findings support the notion of uncontrollable effects of minor contextual cues in face perception, and are consistent with a large body of research that finds people spontaneously encode the context surrounding a face when making social judgements10,11,13,19 (while our focus has been on competence judgements, similar, if attenuated, effects can be observed for other traits, such as trustworthiness; see Supplementary Results and Supplementary Fig. 8). 

The strong and persistent effects we observed are consistent with theoretical work16,18 and empirical findings16,17, showing a robust tendency for people of lower economic status to be perceived as less competent and to be disrespected20, often leading to social exclu-sion with detrimental effects on physical and emotional health21. Poverty is a place where many challenges—physical, social and psychological—converge: being perceived as of lower competence and disrespected adds to those challenges, and can exacerbate cognitive load and hamper performance, thereby potentially prov-ing self-fulfilling22,23. 

To overcome a bias, one needs not only to be aware of it but to have the time, attentional resources and motivation to counteract the bias24. In our studies, we warned participants about the potential bias, presented them with varying lengths of exposure, gave them additional information about the targets and offered financial incen-tives, all intended to alleviate the effect. None of these interventions were effective, however. While it is possible that higher incentives and greater experience could reduce the bias, its persistence in the face of our various manipulations is impressive. 

The present findings demonstrate that economic status cues from clothes naturally intervene in people’s assessments of compe-tence. This is consistent with research showing that people associ-ate status with competence in stereotypes of social groups16,25. This strong status–competence association suggests that any attempt at independen manipulation of the apparent competence and eco-nomic status of a person may need to resort to explicit and salient manipulations, rather than fairly subtle cues. 

The poor clothing cues in our studies were benign compared to real-world poverty signals. Recent work has shown that people can accurately guess others’ social class from brief exposure to photos or speech recordings26. We might thus expect people wearing truly impoverished clothes or exhibiting other peripheral signs of poverty to encounter substantial low-competence stereotyping, both when perceivers think fast as well as when they have more time to deliberate.Stereotypes about rich and poor individuals are common, prom-inent and consequential. Just as the clothing cues in our studies led to differential disambiguation of facial competence, views about a person’s economic background can lead to notably different inter-pretations of what is otherwise ambiguous performance27. Beyond their immediate impact, an important question for future research concerns the extent to which we might be able to transcend first impressions.